You are in: eMedicine Specialties > Radiology > CHEST Swyer-James SyndromeArticle Last Updated: Aug 29, 2002AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Beverly P Wood, MD, MS, PhD, EdD, Professor, Departments of Radiology and Pediatrics, Division of Medical Education, Keck School of Medicine, University of Southern California Beverly P Wood is a member of the following medical societies: American Academy of Pediatrics, American Association for Women Radiologists, American College of Radiology, American Institute of Ultrasound in Medicine, American Medical Association, American Roentgen Ray Society, Association of University Radiologists, Radiological Society of North America, and Society for Pediatric Radiology Editors: Lori Lee Barr, MD, FACR, Clinical Associate Professor of Radiology, Department of Radiology, University of Texas Health Science Center in San Antonio; Member, Board of Directors, Austin Radiological Association; Consulting Staff, Seton Health Network, Columbia/St David's Healthcare System, Healthsouth Rehabilitation Hospotial of Austin and Georgetown Hospital; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Eric J Stern, MD, Director of Thoracic Imaging, Professor of Radiology and Medicine, Departments of Radiology and Internal Medicine, Harborview Medical Center, University of Washington School of Medicine; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Eugene C Lin, MD, Consulting Staff, Department of Radiology, Virginia Mason Medical Center Author and Editor Disclosure Synonyms and related keywords: MacLeod syndrome, unilateral hyperlucent lung, hypogenetic lung, SJS INTRODUCTIONSection 2 of 12
  BackgroundSwyer-James syndrome (SJS) is a manifestation of postinfectious obliterative bronchiolitis. The involved lung or portion of the lung does not grow normally and is slightly smaller than the opposite lung. Radiographically, pulmonary hyperlucency caused by overdistended alveoli combined with diminished arterial flow characterizes its imaging appearance. PathophysiologyThe lung is expected to grow by progressive alveolarization for a child's first 2-8 years. Thereafter, lung growth is related to hyperexpansion of existing alveoli. SJS is a postinfectious syndrome in which diminished vascularity, arrest of progressive growth and alveolarization of the lung, and resultant hypoplasia occur. Multifocal areas of air trapping may be seen. The pulmonary parenchymal pattern is similar to obliterative bronchiolitis. FrequencyUnited StatesAn unusual manifestation, SJS has been described following infection by Mycoplasma pneumoniae and Streptococcus pneumoniae, as well as following severe respiratory syncytial virus infection. Mortality/MorbidityAs a complication of infection, SJS is followed by chronic lung disease showing bronchiolar abnormality, air trapping, and abnormal lung dynamics during inspiration and forced expiration. AgeThe effect of decreased vascularity and lack of growth in the involved lung is characteristic of children younger than 8 years (ie, below the age of complete alveolarization). Radiographically, the imaging findings of SJS appear a few months to a few years following the causative infection. AnatomyPatients with SJS have a small lung, compensatory overexpansion of the contralateral lung, peripheral bronchi and bronchioles "pruned" secondary to obliterative bronchiolitis, a mosaic pattern of hyperlucency on CT, and small vessels and vascular occlusions in the abnormal areas. Clinical DetailsTypically, the child had severe pneumonia earlier in life. SJS effects are as follows:
Organisms causing the infection include respiratory syncytial virus, influenza virus, Mycoplasma pneumoniae, and staphylococcal and streptococcal infections. During differential pulmonary function testing, the involved lung shows diminished flow and oxygenation, and prolonged forced expiratory volume in 1 second. Preferred ExaminationChest CT with thin collimation sections and on inspiration and expiration is the preferred examination. Limitations of TechniquesAn important feature of CT is the appearance of the lungs on forced expiration; therefore, the patient's cooperation is essential. Place the patient in the prone position to help identify the typical mosaic pattern of SJS. DIFFERENTIALSSection 3 of 12
Airway Foreign Body Bronchiolitis Obliterans Organizing Pneumonia Bronchopulmonary Dysplasia Congenital Lobar Emphysema Emphysema
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| Media file 1: Anteroposterior chest radiograph at age 12 months indicates diffuse pneumonia that is clearing on the right. | |
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| Media file 2: Radiograph of the same infant, now age 20 months and cleared of pneumonia, shows a hyperlucent and overexpanded left lung with a small right lung. The patient is asymptomatic at this time. | |
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| Media file 3: At age 4 months, this child has pneumonia centrally throughout the right lung. Pneumonia was caused by a severe respiratory syncytial virus infection. | |
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| Media file 4: Same child as in Picture 3 has severe wheezing and episodes of hypoxemia at age 8 years. Note the small right lung and overexpansion of the left. | |
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| Media file 5: A febrile, ill, 3-month-old infant with rales and rhonchi, which are more severe on the left than the right. | |
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| Media file 6: The same patient as in Picture 5, now aged 12 years. Frontal radiograph shows somewhat small and hyperlucent left lung. The organism causing the original pneumonia was cytomegalovirus. | |
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Article Last Updated: Aug 29, 2002
